package consul import ( "sort" "sync" "time" ) const ( // namespaceEnabledCacheTTL is how long to cache the response from Consul // /v1/agent/self API, which is used to determine whether namespaces are // available. namespaceEnabledCacheTTL = 1 * time.Minute ) // NamespacesClient is a wrapper for the Consul NamespacesAPI, that is used to // deal with Consul OSS vs Consul Enterprise behavior in listing namespaces. type NamespacesClient struct { namespacesAPI NamespaceAPI agentAPI AgentAPI lock sync.Mutex enabled bool // namespaces requires Ent + Namespaces feature updated time.Time // memoize response for a while } // NewNamespacesClient returns a NamespacesClient backed by a NamespaceAPI. func NewNamespacesClient(namespacesAPI NamespaceAPI, agentAPI AgentAPI) *NamespacesClient { return &NamespacesClient{ namespacesAPI: namespacesAPI, agentAPI: agentAPI, } } func stale(updated, now time.Time) bool { return now.After(updated.Add(namespaceEnabledCacheTTL)) } func (ns *NamespacesClient) allowable(now time.Time) bool { ns.lock.Lock() defer ns.lock.Unlock() if !stale(ns.updated, now) { return ns.enabled } self, err := ns.agentAPI.Self() if err != nil { return ns.enabled } sku, ok := SKU(self) if !ok { return ns.enabled } if sku != "ent" { ns.enabled = false ns.updated = now return ns.enabled } ns.enabled = Namespaces(self) ns.updated = now return ns.enabled } // List returns a list of Consul Namespaces. // // TODO(shoenig): return empty string instead of "default" when namespaces are not enabled. (Coming in followup PR). func (ns *NamespacesClient) List() ([]string, error) { if !ns.allowable(time.Now()) { // TODO(shoenig): lets return the empty string instead, that way we do not // need to normalize at call sites later on return []string{"default"}, nil } namespaces, _, err := ns.namespacesAPI.List(nil) if err != nil { return nil, err } result := make([]string, 0, len(namespaces)) for _, namespace := range namespaces { result = append(result, namespace.Name) } sort.Strings(result) return result, nil }